1. Field of the Invention
The present invention relates to a cursor magnifying glass arrangement including a support body and a magnifying glass body having a cylindrical portion and a convexly curved lens section. Both the cylindrical portion and the curved lens section are rotationally symmetrical with respect to the cylindrical axis of the cylindrical portion. An evaluation coil means is disposed coaxially with respect to the cylindrical portion.
2. Background of the Invention
In connection with a known cursor magnifying glass arrangement of this type (see for example German Patent DE-PS 35 20 293), which is particularly suitable for use in connection with digitizing tablets, an evaluation coil means for the generation or detection of a magnetic field is disposed in the outer circumferential area of the cylindrical portion. This evaluation coil means is placed in such a way that it is located in the area between the circumferential surface of the cylindrical portion and the path of edge light beams passing through the edge of the lens section and the cylindrical portion. Therefore, the evaluation coil means is not visible to the viewer when looking through the body of the magnifying glass at the data on the digitizer. This is because the beam of light falling vertically with respect to the data on the outer edge of the lens section is deflected inwardly by the lens section in the direction of the cylindrical axis in such a way that, between it and the outer circumferential surface of the cylindrical portion, an area remains which is unrecognizable to the viewer because of the optical course of the edge light beam. For this reason, an evaluation coil means located in this area is not visible and the viewer only has the impression that this part of the lens body is "opaque".
The evaluation coil means of this known cursor magnifying glass arrangement is disposed with its terminal ends extending through the cylinder body and into the support body where they are connected with a switching device supported in the support body.
For different types of digitizing tablets, manufacturers of digitizing tablets generally provide cursor magnifying glass arrangements comprising different magnifying glass bodies, so that it becomes necessary to use, for each type of digitizing tablet, a magnifying glass arrangement with a magnifying glass body adapted to that digitizer and with a support body which firmly supports it. In addition to this, different magnifying glass bodies are suitable for different applications, so that the user requires specifically designed cursor magnifying glass arrangements, which can be expensive.